Download or read book Prediction of Fatigue Crack Growth Under Variable Amplitude and Spectrum Loading Using a Closure Model written by JC. Newman and published by . This book was released on 1982 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present paper is concerned with the application of an analytical crack-closure model in the study of crack growth under various load histories. The model was based on a concept like the Dugdale model, but modified to leave plastically deformed material in the wake of the advancing crack tip.
Download or read book Fatigue Testing and Analysis Under Variable Amplitude Loading Conditions written by Peter C. McKeighan and published by ASTM International. This book was released on 2005 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prediction of Fatigue crack Growth Under Variableamplitude and Spectrum Loading Using a Closure Model written by and published by . This book was released on 1981 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prediction of Crack Growth Under Variable Amplitude and Spectrum Loading in a Titanium Alloy written by EP. Phillips and published by . This book was released on 2004 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present paper is concerned with the application of a plasticity-induced crack-closure model, FASTRAN, to predict fatigue-crack growth under various load histories in a thin-sheet Ti-62222 STA titanium alloy. This alloy was a leading candidate for a metallic High-Speed-Civil-Transport (HSCT) aircraft in the United States. The crack-growth model was based on the Dugdale strip-yield model but modified to leave plastically deformed material in the wake of the advancing crack. The model includes the influence of "constraint" on the development of plasticity and closure during constant- and variable-amplitude load histories. The model was used to correlate crack-growth-rate data under constant-amplitude loading over a wide range in crack-growth rates and stress ratios at two service temperatures (room temperature and 175°C). Tests on repeated spike overloads were used to help establish the constraint variations in the model. The model was then used to predict crack growth under two simulated aircraft spectrum load histories at the two temperatures. The spectra were a commercial HSCT wing spectrum and the Mini-TWIST (transport wing spectrum). This paper will demonstrate how constraint plays a leading role in the retardation and acceleration effects that occur under variable- amplitude and spectrum loading. The model was able to calculate the effects of repeated spike overloads on crack growth at the two temperatures, generally within about ± 30 %. Also, the predicted crack-growth behavior under the HSCT spectrum agreed well with test data (within 30 %). However, the model under-predicted the fatigue-crack-growth behavior under the Mini-TWIST spectrum by about a factor-of-two. Some of the differences may be due to fretting-product-debris-induced closure or three-dimensional effects, such as free-surface closure, not included in the model. Further study is needed on life predictions under the Mini-TWIST flight spectrum.
Download or read book Methods and Models for Predicting Fatigue Crack Growth Under Random Loading written by and published by ASTM International. This book was released on with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth Under Variable Amplitude Loading written by J. Petit and published by Springer. This book was released on 1988-12-31 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Crack closure Model for Predicting Fatigue crack Growth Under Aircraft Spectrum Loading written by and published by . This book was released on 1981 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Simple Crack Closure Model for Prediction of Fatigue Crack Growth Rates Under Variable Amplitude Loading written by A.U. de Koning and published by . This book was released on 1981 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Crack Closure Model for Predicting Fatigue Crack Growth Under Aircraft Spectrum Loading written by JC. Newman and published by . This book was released on 1981 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments on metallic materials have shown that fatigue cracks remain closed during part of the load cycle under constant- and variable-amplitude loading. These experiments have shown that crack closure is a significant factor in causing load-interaction effects (retardation and acceleration) on crack growth rates under variable-amplitude loading.
Download or read book Fatigue of Structures and Materials written by J. Schijve and published by Springer Science & Business Media. This book was released on 2008-12-16 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue of structures and materials covers a wide scope of different topics. The purpose of the present book is to explain these topics, to indicate how they can be analyzed, and how this can contribute to the designing of fatigue resistant structures and to prevent structural fatigue problems in service. Chapter 1 gives a general survey of the topic with brief comments on the signi?cance of the aspects involved. This serves as a kind of a program for the following chapters. The central issues in this book are predictions of fatigue properties and designing against fatigue. These objectives cannot be realized without a physical and mechanical understanding of all relevant conditions. In Chapter 2 the book starts with basic concepts of what happens in the material of a structure under cyclic loads. It illustrates the large number of variables which can affect fatigue properties and it provides the essential background knowledge for subsequent chapters. Different subjects are presented in the following main parts: • Basic chapters on fatigue properties and predictions (Chapters 2–8) • Load spectra and fatigue under variable-amplitude loading (Chapters 9–11) • Fatigue tests and scatter (Chapters 12 and 13) • Special fatigue conditions (Chapters 14–17) • Fatigue of joints and structures (Chapters 18–20) • Fiber-metal laminates (Chapter 21) Each chapter presents a discussion of a speci?c subject.
Download or read book Fatigue Analyses Under Constant And Variable Amplitude Loading Using Small Crack Theory written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-31 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies on the growth of small cracks have led to the observation that fatigue life of many engineering materials is primarily "crack growth" from micro-structural features, such as inclusion particles, voids, slip-bands or from manufacturing defects. This paper reviews the capabilities of a plasticity-induced crack-closure model to predict fatigue lives of metallic materials using "small-crack theory" under various loading conditions. Constraint factors, to account for three-dimensional effects, were selected to correlate large-crack growth rate data as a function of the effective stress-intensity factor range (delta-Keff) under constant-amplitude loading. Modifications to the delta-Keff-rate relations in the near-threshold regime were needed to fit measured small-crack growth rate behavior. The model was then used to calculate small-and large-crack growth rates, and to predict total fatigue lives, for notched and un-notched specimens under constant-amplitude and spectrum loading. Fatigue lives were predicted using crack-growth relations and micro-structural features like those that initiated cracks in the fatigue specimens for most of the materials analyzed. Results from the tests and analyses agreed well.Newman, J. C., Jr. and Phillips, E. P. and Everett, R. A., Jr.Langley Research CenterCRACK PROPAGATION; FATIGUE LIFE; MICROCRACKS; STRESS INTENSITY FACTORS; DYNAMIC LOADS; FRACTURE MECHANICS; VARIABLE AMPLITUDE LOADING; MICROSTRUCTURE; VOIDS; EDGE DISLOCATIONS; DEFECTS; NOTCHES; CRACK CLOSURE; PLASTIC PROPERTIES
Download or read book A Simple Crack Closure Model for Prediction of Fatigue Crack Growth Rates Under Variable Amplitude Loading written by A. U. de Koning and published by . This book was released on 1981 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Life and Crack Growth Prediction Methodology written by J. C. Newman (Jr) and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prediction of Fatigue Crack Growth Rates Under Variable Loading Using a Simple Crack Closure Model written by A. U. de Koning and published by . This book was released on 1981 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crack Growth Under Spectrum Loading A Crack Closure Model written by and published by . This book was released on 1975 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A concept based on the crack-closure phenomenon was developed to replace random load spectra with constant amplitude loading in both analysis and tests. The maximum load and the crack opening load in the constant amplitude loading are chosen to be equal to those for the spectrum, so that both crack growth mode and the crack length at failure are equivalent to those under random load spectra. The number of cycles of constant- amplitude loading is chosen so that the amount of crack growth is equal to that due to a given sequence or block of the random spectrum loading. The concept was tested experimentally after predicting the equivalent number of constant-amplitude cycles for six different random load sequences. The agreement between predictions and test results was good.
Download or read book Fatigue Analyses Under Constant and Variable Amplitude Loading Using Small Crack Theory written by J. C. Newman (Jr) and published by . This book was released on 1999 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Near Threshold Fatigue Crack Growth Prediction Under Spectrum Loading written by R. Sunder and published by . This book was released on 1992 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A constant crack closure stress-based model assuming the absence of a threshold stress intensity range under spectrum loading forms the basis for a simple procedure to predict crack growth under spectrum loading. The procedure requires material constants that can be derived from constant amplitude fatigue crack growth tests at two stress ratios: (1) at a high stress ratio in the absence of fatigue crack closure, and (2) at a stress ratio corresponding to the most severe cycle under the load spectrum of interest. Crack growth estimates were compared with available experimental data for a variety of materials and load spectra.
